Potential candidates still have until April 15 to file for state and local offices being contested in elections this fall. But already there are some interesting developments in Utah County Republican politics.

Two veteran legislators have decided not to seek re-election this fall, opening the doors of opportunity to other hopefuls.And incumbent Rep. Howard Nielson, who already has two Democrats chasing his 3rd District congressional seat, also may face a challenge from a fellow Republican.

Sen. Paul Rogers, R-Orem, and District 63 Rep. Craig Call, R-Provo, have both made known their intentions not to run again.

Three Republicans, and so far no Democrats, have filed for Rogers' District 17 seat representing north Orem, Lindon and southeast Pleasant Grove. A lone Republican candidate has filed to run in Call's Provo district.

District 59 Rep. Craig A. Peterson, R-Orem, filed to run again in his Utah House of Representatives district when the filing period opened March 15. But Peterson later withdrew from that race and instead filed for Rogers' Senate seat after Rogers decided not to run.

A.L. Bob Wright and D. David Lambert, both of Orem, have also filed for the Senate seat Rogers is vacating. Rogers has said he will support Peterson.

Calvin Monson is the only candidate to have filed so far for the House seat being vacated by Call.

But Nielson faces no shortage of competition for his job in Congress. Democrats Craig Oliver, Taylorsville, and Bob Stringham, Orem, have both announced candidacies. Now Bill Arseneau, a prominent Republican from Provo, is considering a challenge to Nielson for the Republican nomination.

Nielson is aware of the possible Arseneau candidacy, but has told reporters he doesn't expect any Republican challenge. He's also said that such an intraparty battle would likely be a heavy political burden for the challenger to carry into any future campaigns.

Arseneau was among the so-called Gang of Eight who ran for the Republican nomination to the 3rd District seat when it was created in 1982. He later was a Nielson aide and a candidate for the Utah County Commission.

His friends have been hinting for some time that Arseneau may run. But almost no one took the possibility of a Republican challenge to Nielson seriously until industrialist Jon Huntsman proved the unexpected can happen by running against Gov. Norm Bangerter for the GOP gubernatorial nomination.

When asked, Arseneau refused to rule out the possibility of challenging Nielson. But neither is he ready to declare himself a candidate.

"I'm not prepared to say anything right now," he said. "But I want to be up-front about this. I'm certainly looking at it."

Nielson, who is running for a fourth term in Congress, is expected to retire after his next term, should he be re-elected. But he doesn't want to say so publicly because it would make him a lame duck even before the term begins, Nielson believes.

The congressman names Arseneau among half a dozen 3rd District Republicans interested in succeeding him when he retires. Some observers say Arseneau may have no intention of challenging Nielson this year, but might be using the rumors of a challenge to position himself for the 3rd District congressional race of 1990.

Most of the Gang of Eight are said to be still interested in the seat they're expecting Nielson to vacate after one more term. And if a crowded field of GOP hopefuls battles for the seat in 1990 as in 1982, the jockeying for position may begin long before the public campaigning starts.